Wayne Cook
May 1, 1999
Photos By: emap usa Archives

Step By Step

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This photo shows how slick a 5.0 conversion into an early car can be. They’re becoming more and more common.
Shown here is the pre-’88 speed-density air-intake duct. Note that it lacks the mass air meter found on ’88-and-later 5.0L cars.
This underhood shot shows the mass air setup. The air meter is clearly visible on the intake duct, and this also shows the stock airbox, which houses the air cleaner.
Disconnect the air duct and hold the throttle wide open before you use the cleaner. Be sure to run the car immediately after the cleaning.
Remove the stock silencer and install a good free-flow air cleaner, and you’ll pick up some ponies.
These pulleys will help you gain power, and they don’t affect normal operation.
You’ll need a good set of headers, such as these JBA shorties, to open up the exit side of your engine.
This is the aftermarket throttle body all by itself. Installation of one of these is a cinch.
Check out the large ports on this Brodix aluminum head. Heads like this enhance the effort to enlarge the induction passageways in the engine.
Remember to choose your cam carefully because once it’s installed, it’s relatively difficult to change.
The Ford Cobra manifold shown here will open up the breathing on your engine big-time. Cast manifolds such as this one lend themselves well to Extrude Honing.
Tube upper manifolds such as the GT-40 cannot be Extrude Honed.
A good fuel pump, such as this unit from Paxton, is guaranteed to keep your engine well supplied with juice.
This photo shows everything you need to get started in the nitrous game. It’s a simple way to add a lot of horsepower.
In this photo, we are looking at a twin turbo setup that would really honk. But don’t try this at home.
This supercharger installation shows how a modern blower can be concealed underhood.
This is the older Roots-type blower we’re so used to seeing on classic hot rods. There’s no hiding this thing once it’s installed.

We know many of you Ford fans out there are now running the Electronic Engine Control (EEC) IV fuel injection whether your cars are late-model or not. Conversions abound these days because the advantages of EFI are so numerous. You read about our own ’66 Mustang fastback 5.0 EFI conversion in the July ’96 issue of Mustang & Fords, and we know these ideas will apply to a wide spectrum of our readers—conversion Mustang owners, 5.0 types, and other Ford fans. From super smoothness to fantastic reliability and great horsepower numbers, modern fuel injection offers it all.

Contained herein are some tried and true EEC IV EFI tips and tricks drawn from our own experience. We will be touching on converting earlier speed-density fuel-injection control systems to newer, more flexible mass air systems, with a glance at mass air–type advantages as well.

Mass air EFI systems got their start with California-bound ’88 Mustangs with 5.0L engines, and the rest of the nation followed suit in 1989. Speed-density Mustangs lose out on the ability to utilize many of the aftermarket performance parts available for the 5.0L Mustang, because they’re unable to adapt to changing factors caused by changes in engine equipment, such as camshafts and larger throttle bodies. Changes in induction, such as different cylinder heads or a bigger camshaft, confound the system, usually with unsatisfactory results such as rough idle or poor throttle response.

Convert to a mass air system, and these shortcomings are eliminated. You can cam up or add better heads, and the EEC IV processor automatically adjusts to the changes. Changing your pre-’88 engine isn’t difficult, and it’s well worth the effort if performance is your objective. Ford Motorsport SVO offers a complete kit, or you can hunt around and procure the parts yourself. Here in Southern California, Autumn Fleet Sales (AFS)—located at Dept. MF, 7301 Deering Ave., Canoga Park, CA 91303, 818/340-9444—is a good source for late-model donor cars and parts. Mainly an ’87–’93 Mustang boneyard, AFS can help you get started. You’ll need the mass air meter, mass air computer, and air-intake duct. Be sure to specify whether your car is manual or automatic. Once your car is converted to mass air, you’ll have more ways to go about modifying your 5.0 EFI small-block.

Before modifying anything on your car, you can do other things to make sure your mill is at its best. Start with basic stuff like making sure your throttle body is clean. We know from experience that a dirty TB will cause the engine to stall when approaching a stop. This was happening on our 5.0 ’66 fastback conversion. A good cleaning with a specially made throttle-body cleaner made a big difference in our car. The stalling went away, and the engine ran noticeably smoother. Now we do this every 3,000 miles—at every oil change. Make sure your throttle body isn’t labeled for no-solvent use. One trick that costs nothing is to remove the restrictive stock air-intake silencer. Designed to do what it says, it costs about 5 hp. Go one step further and install a high-performance air filter such as the ones available from K&N Engineering (Dept MF, P.O. Box 1329, Riverside, CA 92502, 909/684-9762) for additional performance gains.

Another low-buck trick is to invest in a set of underdrive pulleys. Available from March Performance (Dept. MF, 5820 Hix Rd., Westland, MI 48185, 313/729-9070) or BBK (Dept. MF, 1611 Railroad St., Corona, CA 91720, 909/735-2400), they cost about $100 per set, which is a bargain for the improvement you’ll see. By turning the alternator and water pump at lower speeds, you pick up another 8–10 hp. If you’re skeptical, try turning that alternator or water pump by hand the next time you have the belt off. Just like on a carbureted engine, power can be robbed from a fuelie by a restrictive intake system. While the factory system is adequate for regular use, it doesn’t take much in the way of modification before the remaining stock components begin to fall behind and hamper performance. A good way to start is by installing a larger throttle body.

Equipped from the factory with a 60mm TB (58mm on ’86 5.0s), the engine can be upgraded to a 65mm unit. Our 5.0 conversion ’66 fastback, which has a 65mm Ford Motorsport SVO throttle body, benefits from this upgrade. (You can reach Ford Motorsport Performance Equipment at Dept. MF, 44050 Groesbeck Hwy., Clinton Township, MI 48036. Its tech hotline is 810/468-1356.) The more modifications made to your induction system, the larger the cfm capacity you need. Even modestly modified engines can benefit from 70mm units such as those available from AccuFab (Dept. MF, 1514-B E. Francis, Ontario, CA 91761, 909/930-1751) or BBK.

When intake capacity is increased, exhaust capacity should follow suit. A good set of headers should be somewhat high on your list of improvements. You’ll be surprised at the difference it can make when intake and exhaust modifications go hand in hand. Automotive Engineered Products (Dept. MF, 7149 Mission Gorge Rd., Ste. D, San Diego, CA 92120, 800/830-3377) has JBA shorty headers that are a good choice. Those—combined with high-flow, low-restriction mufflers—will have you standing tall. Look to Flowmaster (Dept. MF, 2975 Dutton Ave, Ste. 3, Santa Rosa, CA 95407, 800/544-4761) or Borla (Dept. MF, 5901 Edison Dr., Oxnard, CA 93033, 805/986-8600) for great high-performance mufflers. While on the subject of the relationship between intake and exhaust, you can make improvements beyond those to the throttle body. With a better-flowing exhaust system in place, consider installing a less restrictive intake manifold.

Several good ones are out there, such as the Ford SVO GT-40. This one flows like gangbusters and bolts right onto your 5.0. Edelbrock (Dept. MF, 2700 California St., Torrance, CA 90503, 310/782-2900) also offers an excellent upper and lower manifold for the 5.0 that will really open up the breathing on your mill.

Cast-aluminum manifolds such as your stock setup, the Edelbrock, or the Ford Cobra have a lot of extra material in them, which means if you want to go further, you can take them to Extrude Hone (Dept. MF, 8800 E. Somerset Blvd., Paramount, CA 90723, 562/531-2976) and have them abrasive-flow-ported. The company’s process forces a special abrasive through the part, producing a mirror-smooth finish as well as enlarging the passageways.

These basic but effective tricks can take you along the path to better performance, and you can go as far as your budget allows. Once you’ve opened up both the top and bottom end with a bigger intake and headers, that leaves the middle. Among the most important gateways to real horsepower are cylinder heads and a camshaft, which dictate engine efficiency when the limits on intake and exhaust are raised.

There are many different ways to go on heads, with cost being one factor. One low-buck choice is to use the heads you already have. Giving them a three-angle valve job is a good first step. This will help smooth out flow over the top of the valve and ensure against any leaks up top. While the heads are off the engine, you can match the intake ports and lower manifold for improved flow. You can do this process yourself using a die grinder with an abrasive tip and plenty of patience. Or you can have a reputable machine shop do it.

If you decide to go with replacement heads, the selection is excellent for the 5.0 Ford. Ford SVO’s GT-40 heads are a good way to go and are available in both cast-iron and aluminum versions. The aluminum GT-40s will save approximately 25 pounds per head. You probably don’t need to be told that this is a huge weight savings which will help on the dragstrip or road course. Other manufacturers of top-quality cylinder heads include Edelbrock, Trick-Flow Specialties (1248 Southeast Ave., Dept. 712051, Tallmadge, OH 44278, 330/630-1555), Holley (Dept. MF, P.O. Box 10360, Bowling Green, KY 42102, 800/HOLLEY1), and Brodix (Dept. MF, P.O. Box 1347, 301 Maple, Mena, AR 71953, 501/394-1075). Most of these heads are made of aluminum.

If you’ve gone this far, then you’re approaching the realm of being faster than a speeding bullet. All channels—intake and exhaust—should be flowing freely, and you’re now in a position to consider a larger camshaft. For street use, choose something in the area of a 0.500-inch lift on intake and exhaust. You can use more radical grinds, but driveability will suffer accordingly. Choose according to your application. If you’re a weekend warrior, then remember all those red lights during the week and err on the conservative side. Your engine will run its best when all of the components harmonize.

Remember: In general, the larger the valve and port size, the higher the camshaft lift will be. And the longer the cam’s duration is, the more the bottom end of the torque-horsepower curve suffers. You will, however, realize more power at the upper range of the curve. But to realize these gains, you have to be willing to wind the engine much tighter. Keep your stock short-block in mind when weighing these choices. If your package doesn’t turn on until four grand, crank and rod strength are factors you may want to consider.

All these modifications will cause your engine to use more fuel. EEC IV fuel injection’s ability to compensate needs help in the form of larger fuel injectors to help prevent a lean condition. Replace stock injectors with 24-liter-per-hour (lph) units as a starting point. Also make sure your fuel pump is up to the task. You may wish to replace your stock 88-lph with a 110-, 155-, or 190-lph unit. This is good insurance, and good pumps are available from many of the previously mentioned manufacturers, as well as from Paxton Products (Dept. MF, 1260 Calle Suerte, Camarillo, CA 93012, 805/987-5555).

A dedicated fuel pump is necessary when you add other step-ups in power production such as nitrous oxide. Nitrous Oxide Systems, 5930 Lakeshore Dr., Dept. 28037, Cypress, CA 90630, 714/821-0580) is a good source for nitrous kits. When added to the air/fuel mixture and exposed to the heat of combustion, nitrous oxide gas turns into pure oxygen. If you’ve ever worked with an acetylene torch, you know what adding oxygen does to the combustion process.

Light the acetylene first, and you get a slow, lazy flame that makes a lot of soot. Add the oxygen—with a little compressed air behind it—and you’re ready to cut a hole in the side of a battleship. Same deal in your motor. The nitrous acts as a combustion intensifier. The more you add, the stronger the boom in your combustion chamber.

There are several ways to go when adding nitrous to your engine. Adding a “fogger plate” between the upper and lower intakes is effective. Higher levels of nitrous can be accomplished with a direct-injection system that shoots directly into the chamber above the intake valve. The manufacturer can advise you on safe-use levels for its particular system as it relates to your engine. Adding nitrous is a relatively simple way to add horsepower. However, it requires refilling the bottle every so often, even if it’s used only intermittently when extra power is desired.

Nitrous can be added anywhere along the buildup process, even as the first step. On a stock engine, about 100hp worth of nitrous works well, and you can use it without doing any of the modifications we’ve talked about so far. However, it’s a temporary power enhancement, because once the bottle is empty, you’re back to square one.

Want to go even further? Well, you’re not out of options yet. Significant power gains can be realized by the tried and true method of increasing displacement. Stroker kits for the 5.0 Ford small-block are available from places like Performance Automotive Warehouse (Dept. MF, 21001 Nordhoff St., Chatsworth, CA 91311, 818/998-6000) and Nowak & Co. (Dept. MF, 249 E. Emerson Ave., Orange, CA 92665, 714/282-7996).

These kits can yield a variety of cubic-inch totals up to a theoretic limit of 377 ci. This figure is beyond what is practical, however, so we recommend no more than 347 ci of displacement, with 331 being a popular stroker displacement.

Limiting factors include the wristpin getting too close to the ring lands on the piston and connecting-rod ratios that can cause side-loading problems. Stroker engines require added machining and block preparation, specially prepared parts, and careful assembly. Still, stroked motors are a viable alternative in the quest for more horsepower, especially when you desire to stay normally aspirated. Of course, you could always combine the two. Forced induction is the next option for increasing horsepower. When you decide to go beyond normal aspiration, you basically have two choices—turbocharging and supercharging. They differ in fundamental ways, yet each produces a similar effect.

The turbocharger compresses the air with a turbine driven by the exhaust gases. Turbos operate at very high rpm, are capable of delivering a lot of boost, and look much like hair dryers. Superchargers essentially do the same thing, but the “blower” is mechanically driven, usually by a drivebelt attached to the crankshaft pulley.

Superchargers look different according to type. Each type increases the air/fuel mixture going into the engine or, in the case of injected engines, just the air (the fuel is added in the usual way).

The extent or level to which they do this is referred to as boost. Air pressure at sea level is 14.7 pounds per square inch, or one atmosphere. Boost is commonly measured in pounds per square inch, so if we run our turbocharger or supercharger at 14.7 pounds boost, the pressure is twice what it normally is at the engine inlet. This is near the top level for street use, and an engine would behave as if it had nearly double its true displacement.

Clearly, we can up the power ante with a turbo or a blower. Each has its advantages and disadvantages, so choose according to your particular application. Turbochargers are quiet, easily concealed, and reliable. They run very hot, though, and consistent lubrication is essential. Superchargers don’t run as hot, but they require horsepower to run and thus result in some parasitic loss. It used to be that you had the unit sticking out through the hood, as with a Roots-type, but centrifugal superchargers can be concealed underhood just like turbos. Both turbos and blowers have adjustable boost levels. If this avenue appeals to you, research it thoroughly to decide which way to go.

Remember that either choice will cause additional strain on all of your engine internals, but especially on the bottom-end components. Four-bolt-main caps on the block, steel cranks, upgraded rods, and forged pistons all require your consideration when cranking up the boost is on your agenda. Things can get expensive, but you’ll have a big smile on your face when the light turns green. When many performance changes are made to an EFI engine, you can go a long way toward smoothing things out with a change in the computer-control chip. Hypertech (Dept. MF, 1910 Thomas Rd., Memphis, TN 38134, 901/382-8888) can help you do this.

When modifications are radical, their presence can be almost completely hidden by changing chips. By this we mean that the rumpity-rump aspect of a hot cam can be partially concealed. Or, if idle quality suffers, a chip change can work wonders to smooth out driveability problems. Most modifications are handled by the stock processor with no problem, and chip changes are only needed in the face of serious performance upgrades. This may include a situation in which many mods have been made on one engine, such as a stroker with a big cam, bigger intake ports, and opened-up cylinder heads.

Many of the modifications we’ve talked about here work best on EFI engines due to those engines’ flexibility. They allow fairly radical stuff, even on street engines, which could cause real driveability problems on a carbureted engine. We know of one chap with a 347 stroker and a 70mm throttle body, a big cam, hogged-out induction, higher compression, big injectors, and more. His car runs very strong but drives around town like a taxicab.

With Ford EEC IV EFI running the show, your list of possible upgrades is a long one. Combine them all and, well, you may be needing a g-force pressure suit!